Rheostat



Nov, 1o, 1925. 1 1,561,137

F. H. BURNS RHEOSTAT Filed May 20, 1922 l/l/ Ill NVEIVTOR.

BY ldzxM/gfb' 1 ATTORNEYS.

Patented Nov. 10, 1925o UNITED STATES P A T FRANK H. BURNS, OF HOOSICK FALLS, NEW 'YOBK, ASSIGNOE, T@ HGOAMSCE FALLS MDI@ PARTS MANUFACTURING COM?, ING., 0F HOOSICK FALLS, NEW YORK,

A.. CORPORATION 0F NEW YORK.

BHEOWTAT.

Application inea nay ao, man. semi ne. esami,

To all whom it may concer/b: Be it known that I, FRANK H. BURNS, a citizen of thevUnied States, residing at Hoosick Falls, in the county of Rensselaer and State of New York, have invented new and useful Improvements in Rheostats, of which the following is a'specification.

Reference may be had to the accompanyingdrawings, and the reference characters marked thereon, which form a part of this `s ecilication. `Similar characters refer to similar parts in the several figures therein.

The principal object of the invention is to provide for quick and accurate adjustment of a rheostat, whereby the resistance to the passage ol an electric current therethrough can' be quickly and accurately varied for various purnoses.,

@ther oh3ectswill appear in connection with the following description.

My invention relates to rheostats-for varions uses, hut is more particularlyadapted lor rheostats for small voltages such as are used in the simpleriforms of radio apparatus. l f

Fig. l of the drawing is a view partly in plan and artly in cross-section o a rheostat embo ying my invention,`the lane of the-,section being axial to the coi of the.

rhe'ostat.

2 is a horizontal section taken throu h the' instrument-board showing in plan t e calibrated members for reading the adjustment of the instrument.

Fi 3 is a half view in front elevation of the r eostat with the projecting handle-portion of the contact-carrymg member shown in cross-section.

Fig. 4 is a viewon an enlarged scale of a broken-away portion of the rheostat as shown in Fig. 1 illustrating the manner in which the, rheostat-coil is mounted in the casing with an 'exposed s iral contact-surface and the manner in w ich said surface is .engaged hy the neighboring contact-member.

Fig. 5 is a cross-section taken in a plane perpendicular tothe axis of the rheostatcoil showing a modiiied form of contactmechanism.

:Referring to the drawings wherein the invention is shown in preferred form, the cas- Afor the rheostat comprises a cu -shaped hody, l, and a cap, 2, iitting an closing mounted thereina rheostat-coil, 3, with an interiorly exposed spiral coil-surface as shown in Figs. l and 4t.

.The mounting of the' coil in this manner within the body of the casing is preferably accomplished by more or less flattenin the wire of which the coil is made and mo ding the insulating material of which the body of the casing is madev upon the outer portion of the wire, leaving the inner portion of the wire exposed "upon the inner 1side of the casing-body.

'lhe inner edge portion of the wire is preferably enlarged as shown in Fig. 4, whereby the wire is firmly anchored in the insulating material.

@ne end oit the coil, 3, is connected with a metal bushing, d, having a binding-screw, 5, whereby a line-wire may he connected `with said bushing, and thus with said end vof the coil, said bushing loeing anchored' to, `or molded within, the lood l, of the casing. A post, 6, is mounte uponthe body of the casing projecting interiorly thereof axially of the coil, 3, said post having a hinding screw, k7, whereby the other line-wire may be connected with said post. The line-wires are not shown in the drawing.

A sleeve, 8, which projects freely through an aperture, 9, in theV cap, 2, receives and lits t ve post, 6, upon which ost said sleeve 1s adapted to move orslide oth longitudinaly `and rotatively.

. pon the outer end of the sleeve, 8, is an operating knob or handle, l0.

Mounted upon the inner end of the sleeve, 8` is a housing, i1, proectin laterallyA from the sleeve at a point w ere t e sleeve is provided with an opening, l2, through its postreceiving portion. f

rllfhe housing, 11, is in fixed relation to the sleeve and partakes of not only the inward and outward sliding movement of the sleeve, but also ol the rotative movement' of the sleeve. y

Mounted within the housing, ll, are a air of contact-members, 13 and 14, separat by amil-spring, i5, tending to torce id contact-members, f

The contact-member, i3, projects through an opening in the inner end of the housing, il, into yielding contact with the metal post, 6` While the contact-member, le,

qprogects through an opening in the outer en o the housing into yielding contact with the exposed coil-surface of the rheostat-coil, 3.

The rheostat is mounted upon an instrument-board, 16, by means of bolts, 17, en-

ageable with the respective lugs, 18, on the ody of the casing, only one of said bolts being shown.

The cap, 2, is secured in place upon the rheostat by means of washers, 19, inserted between the rheosta-t4 and the instrumentboard, and of a size 'to lap the outer side of the cap, 2.

The outer handle-portion of the sleeve, 8, is longitudinally calibratedas shown at 20, whereby the inwardan'd outward movement of the sleeve can be accurately indicated.

rIhe cap, 2, is formed with a central circularly calibrated boss, 21, whereby the rotative movement of 'the sleeve, 8, is accurately indicated. I

The operation of the instrument is as follows:

l/Vhen it is desired to change the resistance of the coil, 3, the sleeve, 8, is, by means ofQ the knob' or handle, 10,",pushed inward orA pulled outward, causing the contact-member, 14 to travel over the exposed coil surface of the rheostat coil, 3, until approximately the desired resistance oi the coil is produced.

By thenrotating the sleeve, 8, more or less in one direction or the other, the resistance can be further varied until the desired resistance is obtained with great enactness.

In movin the contact-member inwardly and outwar ly by direct longitudinal movement of the sleeve, 8, the contact-member, 14, will pass directl. from one loo to another of the coil, 3, e iminating or a ding at each step the resistance of a complete loop oi? the coil.

By the rotative movement of the sleeve, 8, however, the contact-member, le, iscaused to traverse the entire length of a complete loop in the coill in passing from one loop to another, and by imparting' to the sleeveless than a complete rotative movement the resultant chan e in resistance oit the coil can' be made as s ight as desired.

In Fig.. 5 l have shown a portion oi the body, l, of the casing' with a ortion of the exposed spiral coil-surface oir t e coil, 3, and have also shown .the post, d, and a portion of the sleeve, 8, here designated 22.' This portion out the sleeve is interiorly enlarged and has an oset,

Carried by the odset, 23, and the sleeve, 8, is a contact-spring in the forni oi theiigure 3, the inner loop, 2d, of which embraces thev post, 6, while its outer loop, 25, maires contact with the ewosed coil-surface oit coil, 3,

metier" respect to the axis of seid body and in contaci? with the exposedl spiral surface of the co1 v 2. In a rlieostat and in combination, a hollow cylindrical casing of insulating material having a rheostat-coil with an exposed spiral coil surface mounted on 'the inner cylindrical surface of said hollow casing, e plunger `mounted upon the casing axially of said coil and casing with provisions for longitudinal Y and rotative movement with respect to the axis of said coil and casing, and a contact member carried by said plunger in contact with the exposed spiral surface.

3. 4In a rheostat and in combination, a hollow cylindrical casing of insulating material having a rheostat-coil with an exposed spiral coil surface mounted on 'the inner cylindrical surface ci? said hollow casing', a plunger mounted upon the casing axially oi said coil and casing with provisions for longitudinal and rotative movement within the casing and with respect to the anis of said coil and casing, and a Contact member yieldingly mounted and carried by said plunger in contact with the exposed spiral coil surface.

4. In a rheostat and in combination. a hollow cylindrical casing oie insulating man having a rheostat-coil with an exposedspiral coil surface mounted on the inner cylindrical surface of said hollow casing, a. plunger mounted axially and movable within the casing with provisions for longitudinal and rotative movement with respect to the axis oru said casing and coil and having an enteriorly projecting handle, a housing mounted upon said plunger projecting laterally therefrom within said casing, a spring within said housing, and a spring actua-ted Contact member upon said housing and held by projecting outside the casing, and being prosaid spring in yielding contact with the exposed iso vided with an opening through its post-receiving portion, a housing mounted upon the sleeve opposite said opening; and a pair of spring-separated contact-members within said housing, one yieldingly engageablc with said post through said opening and the other yieldingly engageable With the exposled spiral coil-surface of said rheostatco1 6. In a rheostat and in combination, a hollow cylindrical casing of insulating material having a rheostat coil with an exposed spiral coil surface mounted on the interior cylindrical surface of said hollow casing, a

15 plunger mounted axially Within the casing `with provisions for longitudinal and rotative movement With res ct to the axis of said casing and coil and aving calibrations arranged along the longitudinal axis to indicate the amplitude or extent with which said plunger 1s inserted within said casing and coil, a contact member carried by said plunger in contact with the exposed spiral coil surface of said coil, an exteriorly projecting circularly calibrated handle portion on said plunger to indicate the amplitude of rotative movement of said plunger.

In testimony whereof, I have hereunto set my hand this 29th day of April, 1922.

FRANK H. BURNS. 

